The Avantone Pro GTR-100 is a 1U, two-channel Class AB power amplifier designed for guitarists using modelers, pedalboards, and traditional guitar cabinets. It provides 100 watts per channel into 8 ohms, 140 watts per channel into 4 ohms, or 245 watts in bridged mono operation into 8 ohms. The goal is straightforward. Give a carefully built guitar tone enough clean amplification for stage or studio use without adding unnecessary coloration or requiring a traditional tube power amp.
That approach makes particular sense with processors such as the Axe-FX and Quad Cortex, where amp, cabinet, and effect tones are already being shaped upstream. The GTR-100 is designed to preserve those decisions while supplying the power needed to drive physical cabinets.
Stereo and Bridged Mono Operation
The two amplifier channels can operate independently in stereo, which is useful for rigs built around stereo modulation, delay, or other spatial effects. Each channel can feed its own cabinet, allowing the stereo image created by a processor or pedalboard to carry through to the speaker stage.
For applications where maximum output from a single amplifier channel is preferred, the GTR-100 can be switched to bridged mono operation. In this mode, both channels work together to produce 245 watts into an 8-ohm load.
The two-channel architecture can also serve less conventional setups. Each side can function as an independent amplifier, which can be useful when two separate sources or guitar rigs need amplification from the same rack unit.
Line and Instrument Level Inputs
Balanced quarter-inch TRS inputs are provided for both channels, with selectable Line and Instrument input settings. Line mode offers a 20 kΩ input impedance and is intended for processors, modelers, keyboards, and other line-level equipment. Instrument mode provides a 1 MΩ high-impedance input suitable for guitars and stompboxes.
This flexibility means a dedicated modeler is not required. A pedalboard or instrument can feed the amplifier directly when the appropriate input setting is selected.
Four-Band Tone Control
A switchable four-band EQ is built into the front panel for adjustments after the main guitar tone has already been created. This can be useful for adapting a cabinet to a room, stage, or playback environment without changing presets inside the modeler.
The Low control provides up to 10 dB of boost or cut at 87 Hz. Mid provides up to 10 dB at 645 Hz. High provides up to 10 dB at 4.4 kHz, while Air provides up to 7 dB at 11.6 kHz. The EQ can be switched out when no additional correction is required.
Direct Outputs and Analog Cabinet Simulation
The rear panel includes balanced XLR Thru outputs for sending the left and right signals to a mixing console or recording system. This allows the guitar signal to be distributed separately from the speaker outputs, which is useful for live reinforcement and recording.
Each channel also includes a switchable analog cabinet simulation for its corresponding XLR output. According to Avantone, the circuit is designed to approximate the frequency response of an SM57 microphone on a V30-equipped cabinet. This gives the direct output a guitar-cabinet-style response without requiring a microphone on the physical speaker cabinet.
Metering and Front-Panel Monitoring
The GTR-100 includes independent volume controls for the left and right channels along with front-panel output metering. Signal indicators show when audio is present and turn red when clipping is detected.
Additional indicators show power status, bridged operation, EQ activation, and protection status for each channel. These controls make it easier to monitor what the amplifier is doing from the front of a rack without accessing the rear panel.
Electrical Performance
Avantone specifies a frequency response of 20 Hz to 20 kHz within ±0.25 dB and a signal-to-noise ratio greater than 101 dB A-weighted. Total harmonic distortion at 1 kHz is rated below 0.1 percent, as is intermodulation distortion measured at 10 percent of rated power.
Crosstalk is specified at -70 dB, slew rate at 28 V/µs, and damping factor at 275 measured at 100 Hz into 8 ohms. Line input sensitivity is 0.775 V, while instrument input sensitivity is 0.125 V.
The amplifier uses a linear power supply with a toroidal transformer and Class AB amplification.
Built for Rack and Stage Use
The GTR-100 fits into a single standard 19-inch rack space and weighs 7.7 kg, or 17 lb. It can also be used outside a rack with the supplied feet installed for cabinet-top placement.
Fan cooling maintains operating temperature, with air entering through the front vents and exhausting through the rear. Thermal protection can disconnect the loudspeakers and shut the amplifier down if operating temperature becomes excessive. Additional protection circuitry is provided for short circuits and DC voltage at the speaker outputs.
Avantone also specifies rear-mounted rack rails and protective front handles that extend beyond the control knobs, helping reduce the chance of front-panel damage during transport.
A Practical Power Stage for Digital Guitar Systems
For guitarists who already rely on processors or pedalboards to create their core sound, the GTR-100 offers a dedicated way to drive real cabinets while retaining stereo operation, direct outputs, front-panel EQ, and bridged mono capability.
Its combination of line and instrument inputs also keeps it flexible enough for rigs that range from full modeling systems to more traditional pedal-based setups. The rackmount format, output power, analog cabinet simulation, and protection circuitry make it a practical fit for both touring rigs and studio systems where a clean dedicated guitar power amp is required.